JP2015120285A - Ink supply mechanism, ink supply method, and droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink supply mechanism which may stably supply an ink to a droplet discharge head without wasting the ink, and to provide an ink supply method and a droplet discharge device.SOLUTION: An ink supply mechanism 80 includes: an ink tank 81 in which an ink is stored; a filter 82; an open type first sub tank 85 which may control a head pressure of the ink to a droplet discharge head 50; a second sub tank 84 provided between the filter 82 and the first sub tank 85; a first on-off valve 95 provided at the filter 82 side, a second on-off valve 97 provided at the second sub tank 84 side, and a third on-off valve 98 provided at the first sub tank 85 side, in an area between the filter 82 and the first sub tank 85; a first pressure regulation mechanism 91 connected with the ink tank 81; and a second pressure regulation mechanism 92 connected with the second sub tank 84. Capacity of the second sub tank 84 is larger than capacity of the filter 82.

Description

  The present invention relates to an ink supply mechanism, an ink supply method, and a droplet discharge device that supply ink to a droplet discharge head.

  A droplet discharge device such as an ink jet printer includes a droplet discharge head that discharges ink as a droplet from a nozzle, and an ink supply mechanism that supplies ink to the droplet discharge head. In order to stably eject ink from the nozzles of the droplet ejection head, for example, a filter is included in the ink supply mechanism in order to remove foreign matters and bubbles contained in the ink. The filter needs to be replaced depending on the degree of clogging. However, since the filter contains ink, the handling of the filter may be a problem.

For example, Patent Document 1 includes an ink holding container and a supply unit that supplies ink in the ink holding container to a recording nozzle through a filter, and includes a primary side of the filter and an upper air reservoir of the ink holding container. An ink circulation unit of an ink jet recording apparatus is disclosed in which the ink is communicated via an opening / closing means, and ink is sucked from an ink supply path between the secondary side of the filter and the recording nozzle and collected in an ink holding container.
According to the ink circulation unit of Patent Document 1, the ink can be discarded and filled in the filter without staining the hands and the inside of the apparatus with ink, so that maintainability is improved.

JP-A-5-261936

When the ink jet recording apparatus described in Patent Document 1 is used for industrial purposes, if a fine foreign matter contained in the ink is removed using a filter, pressure loss due to the filter during ink supply reduces the pore size of the filter. There is a problem that the ink supply to the recording nozzle becomes unstable. In order to reduce the pressure loss of the filter, a method of enlarging the capacity of the filter is conceivable, but the amount of ink excluded from the inside of the filter increases when the filter is replaced. Therefore, it is required that ink removed from the filter can be effectively reused.
In the ink circulation unit of Patent Document 1, since the ink collected by suction from the ink supply path between the secondary side of the filter and the recording nozzle is returned to the ink holding container, the ink once filtered by the filter is used. There is also a problem that minute foreign matters are mixed again.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 An ink supply mechanism according to this application example is an ink supply mechanism for supplying ink to a droplet discharge head, and includes an ink tank that stores ink, the ink tank, and the droplet discharge A filter provided between the head, an open first sub-tank provided between the filter and the droplet discharge head and capable of controlling a water head pressure of the ink with respect to the droplet discharge head, and the filter A second sub tank provided between the filter and the first sub tank, a first on-off valve provided on the filter side between the filter and the first sub tank, the filter and the first sub tank, A second on-off valve provided on the second sub tank side, and the first sub tank between the filter and the first sub tank. A third open / close valve provided on the side of the ink tank, a first pressure adjusting mechanism connected to the ink tank and capable of controlling the pressure in the ink tank, and connected to the second sub tank, A second pressure adjusting mechanism capable of controlling the pressure of the second sub-tank, wherein a capacity of the second sub tank is larger than a capacity of the filter.

According to this application example, if the second on-off valve is closed, the first on-off valve and the third on-off valve are opened, and the pressure in the ink tank is increased by the first pressure adjusting mechanism, After the stored ink is filtered with a filter, the ink can be stably supplied to the droplet discharge head via the first sub tank capable of adjusting the water head pressure.
When the filter needs to be replaced, the third on-off valve is closed, the first on-off valve and the second on-off valve are opened, and the pressure in the second sub tank is reduced by the second pressure adjustment mechanism. All of the ink filled in the filter can be collected in the second sub tank. Further, during the replacement of the filter, the first on-off valve is closed, the second on-off valve and the third on-off valve are opened, and the ink collected in the second sub tank is dropped through the first sub tank. It can be supplied to the discharge head.
In other words, when replacing the filter, the ink filled in the filter can be used without being discarded, and the time for stopping the ink supply is reduced, so that the ink can be stably supplied to the droplet discharge head. A mechanism can be provided.

In the ink supply mechanism according to the application example, it is preferable that a capacity of the first sub tank is smaller than a capacity of the ink tank.
According to this configuration, it is possible to improve the accuracy of water head pressure management in the first sub tank. That is, it is possible to suppress fluctuations in the ejection amount of ink ejected from the droplet ejection head due to fluctuations in the water head pressure.

In the ink supply mechanism according to the application example, the capacity of the first sub tank is smaller than the capacity of the ink tank, and the capacity of the second sub tank is obtained by adding the capacity of the first sub tank to the capacity of the filter. It may be larger than the value.
According to this configuration, not only the ink filled in the filter but also the ink filled in the first sub-tank is collected in the second sub-tank when, for example, changing the type of ink that requires maintenance of the entire ink supply mechanism. Can be used effectively.

In the ink supply mechanism according to the application example, it is preferable that a bottom area of the second sub tank is larger than a bottom area of the first sub tank.
According to this configuration, even if the liquid levels of the ink in the first sub tank and the second sub tank are the same, the water head pressure in the second sub tank can be made smaller than the water head pressure in the first sub tank. That is, the influence of the water head pressure in the second sub tank on the ink supply to the droplet discharge head can be reduced.

In the ink supply mechanism according to the application example, it is preferable that a pressure sensor that detects a liquid level of ink in the first sub tank is attached to the first sub tank.
According to this configuration, since the liquid level of the ink is detected by the pressure sensor, the ink is less affected by light than when the liquid level is detected by the optical sensor. In other words, ink that is altered or deteriorated by external light or the like can be supplied by managing the water head pressure.

In the ink supply mechanism according to the application example described above, it is preferable that a pressure adjustment valve is provided between the first sub tank and the droplet discharge head.
According to this configuration, since the water head pressure of the ink can be accurately managed by the pressure adjustment valve, it is possible to stably supply the ink to the droplet discharge head without excess or deficiency.

In the ink supply mechanism according to the application example, the first ink supply path that connects the filter and the first sub tank is in the middle of the second ink supply path that connects the first sub tank and the second sub tank. It is preferable to be detachably connected.
According to this configuration, even if the first ink supply path is disconnected from the second ink supply path, ink can be supplied from the second sub tank to the first sub tank. That is, the maintenance for exchanging the ink tank and the filter at the same time can be performed without stopping the supply of ink to the droplet discharge head.

In the ink supply mechanism according to the application example described above, it is preferable that a bubble detection device is provided in the middle of the first ink supply path.
According to this configuration, it is possible to monitor the bubbles in the ink sent from the first ink supply path to the droplet discharge head via the first sub tank. When the number of bubbles is higher than a predetermined level, for example, the ink tank is depressurized using the first pressure adjusting mechanism, or the second sub tank is depressurized using the second pressure adjusting mechanism. The ink can be deaerated.

  [Application Example] An ink supply method according to this application example is an ink supply method for supplying ink to a droplet discharge head, and includes an ink tank in which ink is stored, the ink tank, and the droplet discharge head. A filter provided between the filter and the droplet discharge head, and an open-type first sub-tank that is capable of controlling the water head pressure of the ink with respect to the droplet discharge head, and the first A second subtank provided between the subtank and the filter, and using an ink supply mechanism in which the capacity of the second subtank is larger than the capacity of the filter, from the ink tank to the first subtank. When the ink is supplied to the droplet discharge head and the filter is replaced, the ink in the filter is collected in the second sub tank, Period in which you change the filter is characterized in that the ink recovered into the second sub-tank via the first sub-tank is supplied to the liquid droplet ejection heads.

  According to this application example, when the filter is replaced, the ink filled in the filter can be used without being discarded, and the time for stopping the supply of ink is reduced, so that the ink is stably and efficiently supplied to the droplet discharge head. An ink supply method that can be supplied in an economical manner can be provided.

In the ink supply method according to the application example, the method includes a step of filling the second subtank by filtering the ink in the ink tank with the filter, and filling the second subtank when the ink tank is replaced. Preferably, the ink thus supplied is supplied to the droplet discharge head via the first sub tank.
According to this method, it is possible to provide an ink supply method that can reduce the time for stopping the supply of ink when replacing the ink tank and can efficiently supply the ink filtered by the filter to the droplet discharge head.

[Application Example] A droplet discharge apparatus according to this application example includes a droplet discharge head and the ink supply mechanism described in the above application example.
According to this application example, ink is wasted and ink is stably and efficiently supplied to the droplet discharge head, so that a droplet discharge device having high productivity can be realized.

The liquid droplet ejection apparatus according to the application example described above, further including a carriage on which a plurality of the liquid droplet ejection heads are mounted, and the first sub tank of the ink supply mechanism is disposed on the carriage. preferable.
According to this configuration, it is possible to provide a droplet discharge device that can perform maintenance of the first sub tank as well as the droplet discharge head at the same time without wasting ink by exchanging the carriage.

The schematic perspective view which shows the structure of a droplet discharge apparatus. (A) is a schematic perspective view showing a configuration of a droplet discharge head, (b) is a schematic perspective view showing a structure of a pressurizing portion in the droplet discharge head, and (c) is a structure including a nozzle of the droplet discharge head. FIG. FIG. 3 is a schematic plan view showing the arrangement of droplet discharge heads in the head unit. The block diagram which shows the control system in a droplet discharge apparatus. Schematic which shows the structure of an ink supply mechanism. The schematic perspective view which shows arrangement | positioning of the 1st sub tank and pressure control valve in a carriage. Sectional drawing which shows the detail of a 1st subtank. FIG. 4 is a diagram illustrating a method for supplying ink to a droplet discharge head in a normal state. The figure explaining the step which fills a 2nd sub tank with ink. FIG. 6 is a diagram illustrating an ink supply method to a droplet discharge head when an ink tank is replaced. FIG. 6 is a diagram for explaining an ink supply method to a droplet discharge head when a filter is replaced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

<Droplet ejection device>
First, a droplet discharge device provided with an ink supply mechanism of this embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing the configuration of the droplet discharge device.

  As shown in FIG. 1, the droplet discharge device 10 of this embodiment discharges a liquid (ink) containing a functional material from a droplet discharge head 50 (see FIG. 2A) having a plurality of nozzles. For example, it is a device that discharges to a flat workpiece W. The droplet discharge device 10 includes a workpiece moving mechanism 20 that moves the workpiece W in the main scanning direction (Y-axis direction), and a carriage moving mechanism that moves the carriage 8 in the sub-scanning direction (X-axis direction) orthogonal to the main scanning direction. 30. The droplet discharge head 50 is mounted on the head unit 9 of the carriage 8.

  The workpiece moving mechanism 20 includes a pair of guide rails 21, a moving table 22 that moves along the pair of guide rails 21, and a stage on which the workpiece W disposed on the moving table 22 via the rotating mechanism 6 is placed. And 5.

  The moving table 22 moves in the main scanning direction (Y-axis direction) by an air slider and a linear motor (not shown) provided inside the guide rail 21. The moving table 22 is provided with an encoder 12 (see FIG. 4) as a timing signal generator.

  The encoder 12 reads the scale of a linear scale (not shown) arranged in parallel with the guide rail 21 in accordance with the relative movement of the moving base 22 in the main scanning direction (Y-axis direction), and an encoder pulse as a timing signal. Is generated. The arrangement of the encoder 12 is not limited to this. For example, the moving base 22 is configured to relatively move along the rotation axis in the main scanning direction (Y-axis direction), and a drive unit that rotates the rotation axis is provided. When provided, the encoder 12 may be provided in the drive unit. Examples of the drive unit include a servo motor.

The stage 5 can suck and fix the workpiece W, and the rotation mechanism 6 can accurately align the reference axis in the workpiece W with the main scanning direction (Y-axis direction) and the sub-scanning direction (X-axis direction). ing.
Further, it is possible to turn the workpiece W by, for example, 90 degrees in accordance with the arrangement of ejection areas (also referred to as film formation areas) from which liquid (ink) is ejected on the workpiece W.

  The carriage moving mechanism 30 includes a pair of guide rails 31 and a moving table 32 that moves along the pair of guide rails 31. The moving table 32 is provided with a carriage 8 suspended via a rotation mechanism 7.

A head unit 9 having a plurality of droplet discharge heads 50 (see FIG. 2) mounted on a head plate 9a is attached to the carriage 8.
In addition, the carriage 8 has a part of an ink supply mechanism 80 (see FIG. 4) for supplying liquid (ink) to the droplet discharge heads 50 and electric drive control of the plurality of droplet discharge heads 50. A head driver 72 (see FIG. 4) is provided.
The moving table 32 moves the carriage 8 in the sub-scanning direction (X-axis direction) and disposes the head unit 9 against the workpiece W.

In addition to the above configuration, the droplet discharge device 10 includes a maintenance mechanism that performs maintenance of the plurality of droplet discharge heads 50 mounted on the head unit 9. Examples of the maintenance mechanism include a suction device 110 (see FIG. 4) that eliminates nozzle clogging, and a wiping device (not shown) that removes foreign matters and dirt on the nozzle surface.
The droplet discharge device 10 receives a liquid (ink) discharged from the nozzle of the droplet discharge head 50 as a maintenance mechanism, and measures a weight of the discharged liquid (ink) (not shown). ) Or an observation device (not shown) that can observe the landing state of the ejected liquid (ink). And the control part 40 which controls these structures comprehensively is provided. In FIG. 1, the maintenance mechanism is not shown.

  2A is a schematic perspective view showing the configuration of the droplet discharge head, FIG. 2B is a schematic perspective view showing the structure of the pressure unit in the droplet discharge head, and FIG. 2C is a droplet discharge head. It is a schematic sectional drawing which shows the structure containing these nozzles.

  As shown in FIG. 2A, the droplet discharge head 50 is a so-called double-unit, which is a liquid (ink) introduction unit 51 having two connection needles 52, and is stacked on the introduction unit 51. A head substrate 53 and a head main body 54 disposed on the head substrate 53 and having a liquid (ink) in-head flow path formed therein are provided. The connection needle 52 is connected to the ink supply mechanism 80 described above via a pipe, and supplies liquid (ink) to the flow path in the head. The head substrate 53 is provided with two connectors 57 connected to a head driver 72 (see FIG. 4) via a flexible flat cable (not shown).

  The head main body 54 includes a pressurizing unit 55 having a pressurizing chamber composed of a piezoelectric element as a driving means (actuator), and a nozzle plate in which two nozzle rows 58a and 58b are formed in parallel to each other on the nozzle surface 58p. 56.

  The two nozzle rows 58a and 58b are each arranged on the nozzle surface 58p in a state where a plurality of (for example, 180) nozzles 58 are arranged at substantially equal intervals with a pitch P1, and are shifted from each other by a pitch P2 that is half the pitch P1. Has been. In the present embodiment, the pitch P1 is approximately 141 μm, for example. Therefore, when viewed from the direction orthogonal to the nozzle row 58c formed by the two nozzle rows 58a and 58b, 360 nozzles 58 are arranged at a nozzle pitch of about 70.5 μm. The diameter of the nozzle 58 is approximately 27 μm.

As shown in FIG. 2B, the droplet discharge head 50 includes a nozzle plate 56 in which a plurality of nozzles 58 are formed, a vibration plate 62, and a cavity sandwiched between the nozzle plate 56 and the vibration plate 62. Plate 61.
The cavity plate 61 constituting the pressurizing unit 55 is formed with partition portions 67 that partition the plurality of nozzles 58 and cavities 65 that store liquid (ink). A space partitioned between the nozzle plate 56 and the vibration plate 62 for each nozzle 58 by the partition wall portion 67 is a pressurizing chamber 68. Each partition wall 67 is formed with an orifice (groove) 66 that allows the pressurizing chamber 68 and the cavity 65 to communicate with each other. The diaphragm 62 is provided with a liquid supply port 63 that communicates with the cavity 65. The liquid supply port 63 is connected to the connection needle 52 shown in FIG. 2A, so that the liquid (ink) can be filled into the cavity 65 and each pressurizing chamber 68. The vibration plate 62 is provided with a piezoelectric element 69 corresponding to each pressurizing chamber 68. Such a configuration of the cavity plate 61 is formed corresponding to each of the two nozzle rows 58a and 58b. Specifically, the pressurizing chambers 68 corresponding to the two nozzle rows 58 a and 58 b are arranged with the cavity 65 interposed therebetween.

  As shown in FIG. 2C, in the droplet discharge head 50, when a drive signal as an electric signal is applied from the head driver 72 to the piezoelectric element 69, the diaphragm 62 is deformed and partitioned by the partition wall 67. Volume change of the pressurizing chamber 68 occurs. The liquid (ink) filled in the pressurizing chamber 68 is pressurized by the pump action due to the volume variation of the pressurizing chamber 68, and the liquid (ink) can be ejected as the droplet D from the nozzle 58. On the nozzle surface 58p of the nozzle plate 56, there is formed a protective layer 56a that has been subjected to a liquid repellent treatment that protects the nozzle surface 58p from being damaged and prevents liquid (ink) from adhering to the nozzle surface 58p.

  The driving means (actuator) provided for each nozzle 58 in the droplet discharge head 50 is not limited to the piezoelectric element 69. An electromechanical conversion element that displaces the diaphragm 62 as an actuator by electrostatic adsorption, or an electrothermal conversion element that heats liquid (ink) and discharges it from the nozzle 58 as droplets D may be used.

  Using such a droplet discharge head 50, the droplet D is landed on the film formation region of the work W from the nozzle 58 and solidified, and a thin film made of a functional material contained in the liquid (ink) is formed in the film formation region. The forming method is called a droplet discharge method (inkjet method). In the droplet discharge method, it is necessary to stably apply a predetermined amount of liquid (ink) as droplets D to the film formation region. That is, it is required that the droplet D be ejected while the ejection amount of one droplet is always stable. One of the factors that stabilize the discharge amount of the droplets D is that the liquid (ink) meniscus formation state in the nozzle 58 is stable. This meniscus is affected by the pressure (water head pressure) applied to the liquid (ink) filled in the pressurizing chamber 68. As will be described in detail later, the ink supply mechanism 80 in the present embodiment is configured to be able to supply liquid (ink) to the droplet discharge head 50 at an appropriate water head pressure. In addition, the ink supply mechanism 80 includes an ink tank 81 in which liquid (ink) is stored and a filter 82 (see FIG. 5) that filters foreign matter in the liquid (ink). Replacement of the ink tank 81 and the filter 82 is performed. In some cases, liquid (ink) can be supplied to the droplet discharge head 50 and wasteful consumption of the liquid (ink) can be reduced.

  FIG. 3 is a schematic plan view showing the arrangement of the droplet discharge heads in the head unit. Specifically, it is a view seen from the side facing the workpiece W.

As shown in FIG. 3, the head unit 9 includes a head plate 9a on which a plurality of droplet discharge heads 50 are disposed. In the present embodiment, twelve droplet discharge heads 50 are mounted on the head plate 9a. Each droplet discharge head 50 is arranged such that the nozzle row 58c is along the sub-scanning direction (X direction). In addition, with six droplet discharge heads 50 arranged at equal intervals in the main scanning direction as one head group, two head groups are arranged in parallel in the sub-scanning direction (X direction). In each head group, the six droplet discharge heads 50 are arranged in a state shifted from each other in the sub-scanning direction (X direction). Specifically, as shown in FIG. 3, reference signs H <b> 1 to H <b> 12 are given to the twelve droplet discharge heads 50 arranged in two head groups. Then, when viewed from the main scanning direction, the nozzle row 58c of the droplet discharge head H1, the nozzle row 58c of the droplet discharge head H7, the nozzle row 58c of the droplet discharge head H2, and the nozzle row 58c of the droplet discharge head H8. Are arranged on the head plate 9a so as to be continuous at a predetermined nozzle pitch. More specifically, when the drawing width that can be drawn by one droplet discharge head 50 is L0 and this is the effective length of the nozzle row 58c, the adjacent droplet discharge heads 50 in the main scanning direction (Y direction) are These are arranged with a length of 1/3 of the effective length and shifted in the sub-scanning direction (X direction). As described above, the nozzle row 58c includes two nozzle rows 58a and 58b each having 180 nozzles 58. Therefore, the effective length is a drawing width L0 that can be drawn by 360 nozzles 58. The effective length is not limited to that of 360 nozzles 58, and may be a drawing width that allows drawing by omitting some nozzles 58 positioned on both ends of the nozzle row 58c. The arrangement of the other four droplet discharge heads H3, H4, H9, and H10 and the four droplet discharge heads H5, H6, H11, and H12 is also effective among the nozzle row 58c when viewed from the main scanning direction. The portions are arranged on the head plate 9a so that the portions are continuous at a predetermined nozzle pitch.
According to the arrangement of a plurality (12) of droplet discharge heads 50 on the head plate 9a, a maximum of three different liquids (inks) are discharged with a drawing width L1 that is four times the drawing width L0. It has a possible configuration.

  The number of nozzle rows 58c provided in the droplet discharge head 50 is not limited to two, but may be one. Further, the arrangement of the droplet discharge heads 50 in the head unit 9 is not limited to this.

  Next, a control system of the droplet discharge device 10 will be described with reference to FIG. FIG. 4 is a block diagram showing a control system in the droplet discharge device. As shown in FIG. 4, the control system of the droplet discharge device 10 includes various drivers that drive maintenance mechanisms such as the workpiece moving mechanism 20, the carriage moving mechanism 30, the droplet discharge head 50, the ink supply mechanism 80, and the suction device 110. And a control unit 40 that comprehensively controls the droplet discharge device 10 including the drive unit 70.

  The driving unit 70 drives and controls the moving driver 71 that controls the linear motors of the workpiece moving mechanism 20 and the carriage moving mechanism 30, the head driver 72 that drives and controls the droplet discharge head 50, and the ink supply mechanism 80. And a maintenance driver 74 for driving and controlling the maintenance mechanism.

  The control unit 40 includes a CPU 41, a ROM 42, a RAM 43, and a P-CON 44, which are connected to each other via a bus 45. A host computer 11 is connected to the P-CON 44. The ROM 42 stores a control program area for storing a control program to be processed by the CPU 41, control data for performing a drawing operation, ink supply to the droplet discharge head 50, maintenance processing for the droplet discharge head 50, and the like. And a control data area.

  The RAM 43 includes a drawing data storage unit that stores drawing data for drawing on the workpiece W, a position data storage unit that stores position data of the workpiece W and the droplet discharge head 50 (actually, the nozzle row 58c), and the like. It has various storage units and is used as various work areas for control processing. Various drivers and the like of the drive unit 70 are connected to the P-CON 44, and the logic circuit for supplementing the function of the CPU 41 and handling interface signals with peripheral circuits is configured and incorporated. For this reason, the P-CON 44 receives various commands and the like from the host computer 11 as they are or processes them and imports them into the bus 45, and in conjunction with the CPU 41, the data and control signals output from the CPU 41 and the like to the bus 45 are used as they are. Or it processes and outputs to the drive part 70. FIG.

  Then, the CPU 41 inputs various detection signals, various commands, various data, etc. via the P-CON 44 according to the control program in the ROM 42, processes various data, etc. in the RAM 43, and then drives via the P-CON 44. The entire droplet discharge device 10 is controlled by outputting various control signals to the unit 70 and the like. For example, the CPU 41 controls the droplet discharge head 50, the workpiece moving mechanism 20, and the carriage moving mechanism 30 to place the carriage 8 (head unit 9) and the workpiece W so as to face each other. Then, in synchronization with the relative movement between the carriage 8 (head unit 9) and the workpiece W, liquid (ink) is dropped onto the workpiece W from the plurality of nozzles 58 of each droplet discharge head 50 mounted on the head unit 9. A control signal is sent to the head driver 72 so as to discharge as D. In the present embodiment, discharging liquid (ink) in synchronization with the movement of the workpiece W in the Y-axis direction is called main scanning, and moving the carriage 8 in the X-axis direction with respect to main scanning is sub-scanning. Call it. The droplet discharge device 10 of the present embodiment can discharge a liquid (ink) onto the workpiece W by repeating a combination of main scanning and sub-scanning a plurality of times. The main scanning is not limited to the movement of the workpiece W in one direction with respect to the droplet discharge head 50 but can be performed by reciprocating the workpiece W.

  The encoder 12 is electrically connected to the head driver 72, and generates an encoder pulse with main scanning. In the main scanning, the moving table 22 is moved at a predetermined moving speed, so that encoder pulses are periodically generated.

  For example, assuming that the moving speed of the moving table 22 in main scanning is 200 mm / sec and the driving frequency for driving the droplet discharge head 50 (in other words, the discharge timing when droplets D are continuously discharged) is 20 kHz. The ejection resolution of the droplet D in the scanning direction is 10 μm because it is obtained by dividing the moving speed by the driving frequency. That is, it is possible to arrange the droplets D on the workpiece W with a pitch of 10 μm. The actual ejection timing of the droplets D is based on a latch signal generated by counting periodically generated encoder pulses.

  The host computer 11 sends control information such as a control program and control data to the droplet discharge device 10. Further, it has a function of an arrangement information generation unit that generates arrangement information as ejection control data for arranging a predetermined amount of liquid (ink) as a droplet D for each film formation region on the workpiece W. The arrangement information includes the discharge position of the droplet D in the film formation region (in other words, the relative position between the workpiece W and the nozzle 58), the number of droplets D (in other words, the discharge number for each nozzle 58), the main scanning. Information such as ON / OFF of the plurality of nozzles 58, that is, selection / non-selection of the nozzles 58, ejection timing, and the like is represented as a bitmap, for example. The host computer 11 can not only generate the arrangement information but also modify the arrangement information once stored in the RAM 43.

  Further, the host computer 11 supplies liquid (ink) from the ink supply mechanism 80 to the droplet discharge head 50 based on the ink supply program stored in the ROM 42. A detailed ink supply method will be described later.

  Further, the host computer 11 arranges the droplet discharge head 50 at a position facing the suction device 110 based on the maintenance program stored in the ROM 42, drives the suction device 110, and sets the droplet discharge head 50. The liquid (ink) filled in the droplet discharge head 50 is sucked from the plurality of nozzles 58. Thereby, clogging of the plurality of nozzles 58 (nozzle row 58c) can be eliminated. Hereinafter, a liquid containing a functional material supplied to the droplet discharge head 50 is referred to as ink.

<Ink supply mechanism>
Next, the ink supply mechanism of the present embodiment will be described with reference to FIGS. FIG. 5 is a schematic diagram showing the configuration of the ink supply mechanism. 5 shows the ink supply mechanism 80 including the droplet discharge head 50 and the suction device 110 for convenience.

As shown in FIG. 5, the ink supply mechanism 80 of this embodiment includes an ink tank 81 that stores ink, a filter 82 that is provided between the ink tank 81 and the droplet discharge head 50, and a filter 82. A first sub-tank 85 provided between the droplet discharge head 50 and capable of controlling the water head pressure of the ink with respect to the droplet discharge head 50, and a first sub-tank 85 provided between the filter 82 and the first sub-tank 85. 2 sub-tanks 84.
The details of the ink supply method using the ink supply mechanism 80 will be described later. Basically, after the ink stored in the ink tank 81 is filtered by the filter 82, the liquid droplets are discharged via the first sub tank 85. The head 50 is supplied.

In the ink supply path 88a between the filter 82 and the first sub tank 85, a first opening / closing valve 95 provided on the filter 82 side and a bubble detection device 83 are provided. In the ink supply path 88b between the first sub tank 85 and the second sub tank 84, a second open / close valve 97 is provided on the second sub tank 84 side, and a third open / close valve 98 is provided on the first sub tank 85 side. Yes. The ink supply path 88c between the first sub tank 85 and the droplet discharge head 50 is provided with a fourth open / close valve 99 on the first sub tank 85 side and a pressure adjustment valve 87 on the droplet discharge head 50 side. ing. These ink supply paths 88a, 88b, and 88c are collectively referred to as an ink supply path 88.
The ink supply path 88a corresponds to the first ink supply path in the present invention, and the ink supply path 88b corresponds to the second ink supply path in the present invention.

  The filter 82 can employ, for example, a membrane type or capsule type filter, and is connected via connection parts 93 and 94 so as to be detachable between the ink tank 81 and the first opening / closing valve 95. ing. Further, the ink supply path 88a connected to the filter 82 via the connection portion 94 is connected so as to be detachable between the second opening / closing valve 97 and the third opening / closing valve 98 of the ink supply path 88b. They are connected via the part 96. These connection portions 93, 94, 96 use, for example, a two-way open / close type coupler so that outside air does not enter the respective ink supply paths 88 a, 88 b when being attached / detached. The two-way open / close type coupler is configured such that both paths communicate with each other when connected, and both paths are closed when disconnected. In addition, by providing a bubble detection device 83 in the ink supply path 88a, it is detected whether or not bubbles are included in the filtered ink, and whether or not bubbles have entered when the ink supply path 88a is attached or detached is also detected. can do. The method of the bubble detection device 83 is not particularly limited, but in the present embodiment, in consideration of ink alteration and deterioration due to light, bubble detection by microwave is adopted instead of optical bubble detection. Yes. Specifically, by irradiating the ink supply path 88a with microwaves and detecting the reflected waves, it is possible to determine whether the ink contains bubbles or not.

  A first pressure adjusting mechanism 91 that can control the pressure in the ink tank 81 is attached to the ink tank 81. The first pressure adjustment mechanism 91 is, for example, a pump that sends gas into the ink tank 81 to pressurize it. Since the filter 82 is provided in the ink supply path 88a between the ink tank 81 and the first sub tank 85, the first pressure adjusting mechanism capable of supplying ink in consideration of pressure loss when the ink is filtered by the filter 82. 91 abilities are required. The ink tank 81 may be formed using a rigid steel material such as stainless steel, or may be a cartridge type in which a flexible ink pack is accommodated in the rigid tank.

  A second pressure adjusting mechanism 92 that can control the pressure in the second sub tank 84 is attached to the second sub tank 84. The second pressure adjusting mechanism 92 is, for example, a pump that sends and pressurizes gas into the second sub-tank 84 and sucks and decompresses gas in the second sub-tank 84. As a result, the inside of the second sub tank 84 is pressurized to send the ink in the second sub tank 84 to the ink supply path 88b, or the inside of the second sub tank 84 is depressurized and the ink is supplied from the ink supply path 88b to the second sub tank 84. It can also be filled.

  The second sub tank 84 is formed using a steel material such as stainless steel, and the capacity of the second sub tank 84 is at least larger than the capacity of the filter 82. In the present embodiment, the capacity of the second sub tank 84 is larger than the value obtained by adding the capacity of the first sub tank 85 to the capacity of the filter 82.

  The first sub tank 85 is an open type communicating with the atmosphere, and temporarily stores the ink injected through the ink supply path 88b. A pressure sensor 86 is attached to the first sub tank 85, and the liquid level of the ink in the first sub tank 85 can be detected by the pressure sensor 86 as a liquid pressure. By detecting the ink level in the first sub tank 85, the head pressure of ink supplied from the first sub tank 85 to the droplet discharge head 50 via the ink supply path 88c can be controlled. It has become. In addition, a pressure adjustment valve 87 is provided between the first sub tank 85 and the droplet discharge head 50. The pressure regulating valve 87 is, for example, a diaphragm type self-sealing valve. By providing the pressure adjusting valve 87, ink can be supplied to the droplet discharge head 50 without excess or deficiency according to the water head pressure of the ink and the negative pressure state of the cavity 65 of the droplet discharge head 50. Although the detailed configuration of the first sub tank 85 will be described later, the first sub tank 85 is arranged such that the longitudinal direction thereof is along the vertical direction. The bottom area of the first sub tank 85 is smaller than the bottom area of the second sub tank 84, in other words, the bottom area of the second sub tank 84 is larger than the bottom area of the first sub tank 85. As a result, the first sub tank 85 is less susceptible to the ink head pressure in the second sub tank 84.

Here, the suction device 110 will be described with reference to FIG.
The suction device 110 recovers clogging of the nozzle 58 by sealing (capping) the nozzle surface 58p of the droplet discharge head 50 and sucking ink or bubbles in the droplet discharge head 50 from the nozzle 58. It is a device to let you. The suction device 110 includes a cap 111 that seals the nozzle surface 58p, a recovery tank 112 that recovers the sucked ink, and a negative pressure unit 113 that can make the pressure in the recovery tank 112 negative. . The negative pressure means 113 can employ a rotary pump, for example. The cap 111 has a tray shape in which an abutting member made of an elastic member such as rubber or the like is arranged around the nozzles 58 on the nozzle surface 58p. An open / close valve 114 is provided between the cap 111 and the recovery tank 112.
Such a suction device 110 not only performs the operation of sealing and sucking the nozzle surface 58p but also the ink preliminarily discharged from the plurality of nozzles 58 of the droplet discharge head 50 without sealing the nozzle surface 58p. A receiving operation is also possible. The suction device 110 may be provided for each droplet discharge head 50, or may be provided corresponding to a plurality of droplet discharge heads 50 mounted on the carriage 8.

Next, the relationship between the carriage 8 and the ink supply mechanism 80 will be described with reference to FIG. FIG. 6 is a schematic perspective view showing the arrangement of the first sub tank and the pressure regulating valve in the carriage.
As shown in FIG. 6, the first sub tank 85 and the pressure adjustment valve 87 are attached to the carriage 8. A pressure sensor 86 and a fourth opening / closing valve 99 associated with the first sub tank 85 are also attached to the carriage 8.

  The ink supply path 88c that connects the first sub tank 85 and the pressure adjustment valve 87 via the fourth opening / closing valve 99 and the ink supply path 88d that connects the pressure adjustment valve 87 and the droplet discharge head 50 are both flexible. For example, a tube such as polyethylene terephthalate is used. Further, in this embodiment, even when an ink containing, for example, an organic electroluminescence material or an ultraviolet curable ink is used, the light shielding property is prevented so that the ink does not deteriorate or deteriorate. The tube which has is used.

In the present embodiment, four droplet discharge heads 50 are connected to one pressure adjustment valve 87 via an ink supply path 88d. As described above, the head plate 9a of the head unit 9 has twelve droplet discharge heads 50 mounted thereon, and ink can be discharged with a drawing width L1 with four droplet discharge heads 50 as one set. This is because it has a simple structure (see FIG. 3). In other words, FIG. 6 shows a configuration in which ink can be supplied for each type to the plurality of droplet discharge heads 50 mounted on the carriage 8. Accordingly, although not shown in FIG. 6, in reality, in order to supply ink to the twelve droplet discharge heads 50, the carriage 8 has three first sub tanks 85 and three pressure regulating valves. 87 is attached.
Different types of ink may be injected into each of the three first sub tanks 85, or the same type of ink may be injected. Also, it is possible to inject different ink into one of the three first sub tanks 85 in one of the first sub tanks 85.

Next, a detailed configuration of the first sub tank 85 will be described with reference to FIG. FIG. 7 is a cross-sectional view showing details of the first sub tank.
As shown in FIG. 7, the first sub tank 85 is a tubular container made of, for example, stainless steel having excellent corrosion resistance and light shielding properties. The first sub tank 85 is attached to the carriage 8 described above so that the longitudinal direction thereof is in the vertical direction. A gas inlet 85d is provided at one end (upper end in the drawing) of the first sub-tank 85 and is open to the atmosphere. An ink inflow port 85 a is provided on the side surface on one end side of the first sub tank 85.

  A fitting 85c having an ink discharge port 85b is connected to the other end (lower end in the drawing) of the first sub tank 85. A pressure sensor 86 is attached to the side surface of the mounting bracket 85c. The pressure sensor 86 is attached to the mounting bracket 85 c so that the pressure receiving surface is along the longitudinal direction of the first sub tank 85. An ink supply path 88c and a fourth open / close valve 99 are connected to the ink discharge port 85b.

The pressure sensor 86 outputs an electric signal corresponding to the liquid pressure corresponding to the liquid level of the ink 1 injected into the first sub tank 85. In particular, the control unit 40 detects the first signal corresponding to the first liquid level LL1 that is almost full and the second signal corresponding to the second liquid level LL2 that is lower than the first liquid level LL1. It is possible. That is, the liquid level of the first sub tank 85, that is, the water head pressure, is managed between the first liquid level LL1 and the second liquid level LL2.
In the present embodiment, the inner diameter of the first sub tank 85 is, for example, 16 mm, and the length of the first sub tank 85 is, for example, 250 mm. Therefore, the volume of the first sub tank 85 is approximately 50 cm ³ . Therefore, for example, when 1 cm ³ of ink is injected into the first sub tank 85, the liquid level rises by 5 mm. In the present embodiment, the difference ΔLL between the first liquid level LL1 and the second liquid level LL2 is 10 mm. That is, the water head pressure is managed in the ink amount range corresponding to 2 cm ³ .

The bottom area inside the first sub tank 85 in this embodiment is 2 cm ² . As described above, the capacity of the second sub tank 84 is larger than the value obtained by adding the capacity of the first sub tank 85 (50 cm ³ ) to the capacity of the filter 82. The bottom area inside the second sub tank 84 is set larger than the bottom area (2 cm ² ) of the first sub tank 85.

  The capacity of the first sub tank 85 is determined in consideration of the number of droplet discharge heads 50 connected to one first sub tank 85 and the amount of ink discharged from the droplet discharge head 50 by main scanning. In the present embodiment, when one type of ink is ejected to one work W, the amount of ink ejected from the four droplet ejection heads 50 is the first liquid level LL1 and the second level of the first sub tank 85. The difference ΔLL with respect to the liquid level LL2 is set slightly above. Although it is possible to set the difference ΔLL so as to correspond to the amount of ink when one kind of ink is ejected to a plurality of workpieces W, if this is done, the difference in ink head pressure becomes large, as described above. In addition, the shape of the meniscus in the nozzle 58 may vary, and it may be difficult to achieve a stable discharge amount of the droplet D.

The capacity of the first sub tank 85 is 50 cm ³ as described above, and is set in consideration of the amount of ink that needs to be supplied to the droplet discharge head 50 during main scanning and the management level of the water head pressure. Therefore, it is considerably smaller than the capacity of the ink tank 81 in which the ink 1 is stored. In this embodiment, the ink tank 81 has a capacity of about 700 cm ³ , the second sub tank 84 has a capacity of about 1000 cm ³ , and the filter 82 has a capacity of about 100 cm ³ .

  The fourth open / close valve 99 connected to the flexible ink supply path 88c has a height between the ink inlet 85a and the ink outlet 85b of the first sub tank 85 in the vertical direction. It arrange | positions with respect to the 1st sub tank 85 so that it may be located in a place lower than the rank LL2. As a result, even if bubbles are included in the ink 1 as compared with the case where the fourth opening / closing valve 99 is disposed below the ink discharge port 85b, the bubbles pass through the fourth opening / closing valve 99. It becomes difficult to be sent to the droplet discharge head 50.

  In order to accurately detect the liquid level of the ink 1 injected into the first sub tank 85 by the pressure sensor 86, the pressure sensor is selected according to the location on the earth where the droplet discharge device 10 having the ink supply mechanism 80 is installed. 86 calibrations are required. It is considered that calibration is necessary each time the installation location of the droplet discharge device 10 is moved. Further, it is considered that calibration is necessary depending on the type of ink 1 injected into the first sub tank 85.

  As a method for calibrating the pressure sensor 86, for example, the fourth on-off valve 99 is closed, the ink 1 is injected into the first sub tank 85 from the ink inlet 85a, and the ink 1 is full until it overflows from the gas inlet 85d. And At this time, the distance from the center of the pressure receiving surface of the pressure sensor 86 to the gas inlet 85d is measured, and an electric signal corresponding to the hydraulic pressure sensed by the pressure sensor 86 at that time is used as a calibration signal. Based on the signal level for calibration, there is a method of setting the levels of the first signal corresponding to the first liquid level LL1 and the second signal corresponding to the second liquid level LL2. It is done.

  Such an ink supply mechanism 80 is electrically controlled by the control unit 40 and the ink supply driver 73 as described above. Specifically, the pressure sensor 86, the first pressure adjustment mechanism 91, the second pressure adjustment mechanism 92, and the open / close valves 95, 97, 98, and 99 of the ink supply mechanism 80 are electrically connected to the control unit 40. . As a result, the control unit 40 causes the ink 1 stored in the ink tank 81 to be stably supplied to the droplet discharge head 50, and is supplied to the droplet discharge head 50 when the ink tank 81 is replaced or when the filter 82 is replaced. Control can be performed so that the supply of ink 1 is not stopped. Further, it is possible to control so that the ink 1 is not wasted at the time of maintenance including the replacement. Hereinafter, a detailed ink supply method will be described.

<Ink supply method>
An ink supply method using the ink supply mechanism 80 of the present embodiment will be described with reference to FIGS. FIG. 8 is a diagram for explaining an ink supply method to the droplet ejection head in a normal state, FIG. 9 is a diagram for explaining steps for filling the second sub tank with ink, and FIG. 10 is a droplet ejection head at the time of replacing the ink tank. FIG. 11 is a diagram for explaining the ink supply method to the droplet discharge head when the filter is replaced.

  The control unit 40 closes the second opening / closing valve 97 and performs the first opening / closing operation at the normal time (when the main scanning for discharging the ink 1 from the droplet discharge head 50 to the workpiece W is performed by the droplet discharge device 10). The valve 95, the third on-off valve 98, and the fourth on-off valve 99 are opened. Then, the ink tank 81 is pressurized by the first pressure adjusting mechanism 91, and as shown in FIG. 8, the ink 1 in the ink tank 81 is filtered by the filter 82, and passes through the ink supply paths 88a and 88b to form the first sub tank. 85 is injected. As described above, the liquid level of the ink 1 in the first sub tank 85 is detected by the pressure sensor 86, and when the control unit 40 detects the first signal corresponding to the first liquid level LL1, the liquid level to the first sub tank 85 is supplied to the first sub tank 85. Ink 1 injection is stopped. Further, when the control unit 40 detects the second signal corresponding to the second liquid level LL2, the ink 1 is injected into the first sub tank 85. In the droplet discharge head 50, the ink 1 passes through the pressure adjustment valve 87 according to the liquid level (water head pressure) of the ink 1 in the first sub tank 85 and the negative pressure state of the cavity 65 of the droplet discharge head 50. Is supplied.

  When the main scanning for discharging the ink 1 to the workpiece W is completed, the control unit 40 closes the fourth open / close valve 99 and the liquid level in the first sub tank 85 is changed to the first level according to the output from the pressure sensor 86. Ink 1 is replenished so that the liquid level LL1 is 1.

  When the main scanning is not performed, the control unit 40 closes the third opening / closing valve 98 and the fourth opening / closing valve 99 and pressurizes the ink tank 81 by the first pressure adjusting mechanism 91, As shown in FIG. 9, the ink 1 filtered by the filter 82 is filled into the second sub tank 84 via the ink supply paths 88a and 88b. The filling amount of the ink 1 into the second sub tank 84 is determined based on the amount of the ink 1 filtered per unit time when the ink 1 is filtered by the filter 82 with a predetermined pressure applied to the ink tank 81. It can be obtained by controlling the pressurization time of

When the controller 40 detects the output of the pressure sensor 86 and determines that no change in the liquid level is recognized even after a predetermined time has elapsed during the injection of the ink 1 into the first sub tank 85, It is determined that the ink tank 81 is almost empty.
When determining that the ink tank 81 is almost empty, the control unit 40 closes the first opening / closing valve 95 and opens the second opening / closing valve 97 and the third opening / closing valve 98. Then, as shown in FIG. 10, the second sub tank 84 is pressurized by the second pressure adjusting mechanism 92, and the ink 1 filled in the second sub tank 84 is injected into the first sub tank 85 via the ink supply path 88b. To do. Since the liquid level in the first sub tank 85 is detected by the pressure sensor 86, the controller 40 can control the injection / stop of the ink 1 from the second sub tank 84 to the first sub tank 85.

  If the connection portion 93 is removed during a period in which the ink 1 can be supplied from the second sub tank 84 to the first sub tank 85, the ink tank 81 can be replaced without stopping the supply of the ink 1 to the droplet discharge head 50. it can. Further, if the connecting portion 96 is removed, the maintenance of the ink supply path 88a including the filter 82 and the bubble detection device 83 can be performed without stopping the supply of the ink 1.

  In addition, after the ink tank 81 is replaced, when the ink supply path 88a is again connected to the ink supply path 88b and the ink 1 is supplied from the ink tank 81, if the ink 1 contains bubbles, the bubble is detected. When the apparatus 83 detects, the control unit 40 can close the third opening / closing valve 98 and open the second opening / closing valve 97 to fill the second sub tank 84 with the ink 1 containing bubbles. Since the second sub tank 84 is provided with the second pressure adjusting mechanism 92 as described above, the ink in the second sub tank 84 can be obtained by closing the second on-off valve 97 and depressurizing the second sub tank 84. It is also possible to degas 1. That is, the configuration including the second sub tank 84 and the second pressure adjusting mechanism 92 also functions as a degassing device for the ink 1.

Further, the control unit 40 detects the output of the pressure sensor 86, so that when the liquid level is small even after a predetermined time has elapsed during the injection of the ink 1 into the first sub tank 85, that is, the ink. When the injection speed of 1 does not reach the predetermined value, it is determined that the filter 82 is clogged and the pressure loss in the supply of the ink 1 has increased. Then, it is notified that the filter 82 needs to be replaced.
When determining that the filter 82 needs to be replaced, the control unit 40 closes the third opening / closing valve 98 and opens the first opening / closing valve 95. The connection portion 93 on the upstream side of the filter 82 is removed, so that outside air can be introduced. Then, as shown in FIG. 11, the second sub tank 84 is depressurized by the second pressure adjusting mechanism 92, and the ink 1 in the filter 82 is sucked and collected in the second sub tank 84. When the suction of the predetermined time is performed and the collection of the ink 1 in the filter 82 is completed, the control unit 40 closes the first opening / closing valve 95 and pressurizes the second sub tank 84 by the second pressure adjusting mechanism 92. Then, the ink 1 collected in the second sub tank 84 is injected into the first sub tank 85 through the ink supply path 88b. If the connection portions 93 and 94 are removed during a period in which the ink 1 can be supplied from the second sub tank 84 to the first sub tank 85, the filter 82 can be replaced without stopping the ink supply to the droplet discharge head 50. .

Although what kind of ink 1 is used in the ink supply mechanism 80 is a matter of design, for example, the ink 1 containing an organic electroluminescent material is expensive and easily deteriorated or deteriorated by light such as ultraviolet rays. In addition, when a light emitting layer or the like is formed using such an ink 1 by a droplet discharge method, a dark spot is generated in which light emission cannot be obtained from that portion even if a minute foreign substance of, for example, submicron exists in the light emitting layer. There is a fear. Therefore, a filter 82 having a submicron pore diameter is selected. However, as the pore diameter decreases, the pressure loss during the filtration of the ink 1 increases. As a method for reducing the pressure loss during filtration, it is conceivable to increase the filtration area, that is, the capacity of the filter 82, but the ink 1 is wasted when the filter 82 is replaced. Moreover, since the filtration life of the filter 82 becomes shorter as the hole diameter is smaller, the replacement frequency of the filter 82 increases.
According to the ink supply method using the ink supply mechanism 80 of the present embodiment, wasteful consumption of the ink 1 in replacement of the filter 82 can be reduced even if the hole diameter of the filter 82 is set to submicron.

The effect of the said embodiment is as follows.
(1) According to the ink supply mechanism 80 and the ink supply method using the ink supply mechanism 80, the ink 1 is supplied to the droplet discharge head 50 through the first sub tank 85 and the pressure adjustment valve 87 that can control the water head pressure. Therefore, the ink 1 can be stably supplied to the droplet discharge head 50 without excess or deficiency.
(2) When the ink tank 81 is replaced or when the filter 82 is replaced, the ink 1 filtered and filled in the second sub tank 84 can be supplied to the first sub tank 85. The ink tank 81 and / or the filter 82 can be replaced without stopping the ink supply.
(3) Since the ink 1 in the filter 82 can be collected in the second sub tank 84, it is possible to reduce the ink 1 that is discarded when the filter 82 is replaced.
(4) The droplet discharge device 10 provided with the ink supply mechanism 80 can shorten the time during which the operation of the device is stopped as the ink tank 81 is replaced or the filter 82 is replaced. 1 can be discharged.
(5) Since the first sub tank 85, the pressure adjustment valve 87, and the fourth open / close valve 99 of the ink supply mechanism 80 are attached to the carriage 8, the first sub tank 85, Maintenance or replacement of the pressure regulating valve 87 and the fourth on-off valve 99 can be performed.

  The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. An ink supply method and a droplet discharge device to which the ink supply mechanism is applied are also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

  (Modification 1) The configuration of the droplet discharge device 10 is not limited to this. For example, a plurality of carriages 8 may be provided according to the size of the workpiece W instead of one. Further, the number and arrangement of the droplet discharge heads 50 mounted on the carriage 8 are not limited to this.

  (Modification 2) The configuration of the ink supply mechanism 80 is not limited to this. For example, the number of ink tanks 81 connected to the ink supply path 88a is not limited to one, and a plurality of ink tanks 81 may be arranged. Further, the number of filters 82 connected to the ink supply path 88a is not limited to one. For example, a plurality of filters having different hole diameters may be arranged in series.

  DESCRIPTION OF SYMBOLS 8 ... Carriage, 10 ... Droplet discharge apparatus, 40 ... Control part, 50 ... Droplet discharge head, 80 ... Ink supply mechanism, 81 ... Ink tank, 84 ... Second sub tank, 85 ... First sub tank, 85a ... Ink flow Inlet, 85b ... Ink discharge port, 86 ... Pressure sensor, 87 ... Pressure adjustment valve, 88, 88a, 88b, 88c, 88d ... Ink supply path, 91 ... First pressure adjustment mechanism, 92 ... Second pressure adjustment mechanism, 95 ... 1st on-off valve, 97 ... 2nd on-off valve, 98 ... 3rd on-off valve, 99 ... 4th on-off valve, 110 ... Suction device.

Claims (12)

An ink supply mechanism for supplying ink to a droplet discharge head,
An ink tank for storing ink;
A filter provided between the ink tank and the droplet discharge head;
An open first sub-tank provided between the filter and the droplet discharge head and capable of controlling a water head pressure of the ink with respect to the droplet discharge head;
A second sub tank provided between the filter and the first sub tank;
A first on-off valve provided on the filter side between the filter and the first sub tank;
A second on-off valve provided on the second sub-tank side between the filter and the first sub-tank;
A third on-off valve provided on the first sub tank side between the filter and the first sub tank;
A first pressure adjusting mechanism connected to the ink tank and capable of controlling the pressure in the ink tank;
A second pressure adjusting mechanism connected to the second sub tank and capable of controlling the pressure in the second sub tank;
The ink supply mechanism according to claim 1, wherein a capacity of the second sub tank is larger than a capacity of the filter.   The ink supply mechanism according to claim 1, wherein the capacity of the first sub tank is smaller than the capacity of the ink tank. The capacity of the first sub tank is smaller than the capacity of the ink tank,
2. The ink supply mechanism according to claim 1, wherein a capacity of the second sub tank is larger than a value obtained by adding a capacity of the first sub tank to a capacity of the filter.   4. The ink supply mechanism according to claim 1, wherein a bottom area of the second sub tank is larger than a bottom area of the first sub tank. 5.   5. The ink supply mechanism according to claim 1, wherein a pressure sensor that detects a liquid level of the ink in the first sub tank is attached to the first sub tank. 6.   The ink supply mechanism according to any one of claims 1 to 5, further comprising a pressure adjustment valve between the first sub tank and the droplet discharge head.   The first ink supply path that connects the filter and the first sub tank is detachably connected in the middle of the second ink supply path that connects the first sub tank and the second sub tank. The ink supply mechanism according to any one of claims 1 to 6.   The ink supply mechanism according to claim 7, wherein a bubble detecting device is provided in the middle of the first ink supply path. An ink supply method for supplying ink to a droplet discharge head,
An ink tank for storing ink;
A filter provided between the ink tank and the droplet discharge head;
An open first sub-tank provided between the filter and the droplet discharge head and capable of controlling a water head pressure of the ink with respect to the droplet discharge head;
A second sub tank provided between the first sub tank and the filter, and using an ink supply mechanism in which the capacity of the second sub tank is larger than the capacity of the filter,
Supplying ink from the ink tank to the droplet discharge head via the first sub tank;
When replacing the filter, the ink in the filter is collected in the second sub tank, and during the period when the filter is replaced, the ink collected in the second sub tank passes through the first sub tank. An ink supply method comprising supplying to the droplet discharge head. Filtering the ink in the ink tank with the filter and filling the second sub-tank;
10. The ink supply method according to claim 9, wherein when the ink tank is replaced, the ink filled in the second sub tank is supplied to the droplet discharge head via the first sub tank. A droplet discharge head;
A liquid droplet ejection apparatus comprising: the ink supply mechanism according to claim 1. A carriage having a plurality of droplet discharge heads mounted thereon;
The liquid droplet ejection apparatus according to claim 11, wherein the first sub tank of the ink supply mechanism is disposed on the carriage.

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